Leveling compositions

ABSTRACT

The present disclosure is drawn to leveling compositions, embossed print media, and methods of preparing embossed print media. The embossed print media can include a media substrate, an image-receiving layer applied to the media substrate at a coating weight of 3 gsm to 50 gsm, and a leveling composition layer. The image-receiving layer can include a pigment filler having an average particle size ranging from 0.1 μm to 20 μm and a polymeric binder, and in examples herein, is embossed. The leveling composition layer can be applied at a coating weight of 0.2 gsm to 3 gsm to the image-receiving layer, and can include a cationic ionene polymer.

The present application is a divisional of U.S. patent application Ser.No. 15/742,068, filed on Jan. 5, 2018, which was a national stageapplication of PCT/US2015/050931, filed on Sep. 18, 2015, both of whichare incorporated herein by reference in their entireties.

BACKGROUND

Inkjet printing technology has been used in all fields of printingapplications, from traditional home and office usage to high-speed,commercial, and industrial printing. This is, in part, because of itsability to produce economical, high quality, multi-colored prints.Various types of media have been used for inkjet imaging, includingporous media, smooth media, offset media, coated media, etc. Media withtexture has also been used for printing substrates, but the use of suchtextured media can be challenging for certain print technologies.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional features and advantages of the disclosure will be apparentfrom the detailed description which follows, taken in conjunction withthe accompanying drawings, which together illustrate, by way of example,features of the present technology.

FIG. 1 is a cross-sectional view of an embossed print medium with animage-receiving layer, but without a leveling composition layer, inaccordance with examples of the present disclosure;

FIG. 2 is a cross-sectional view of an embossed print medium as shown inFIG. 1, but which includes a leveling composition layer that was appliedafter the print medium was embossed in accordance with examples of thepresent disclosure;

FIG. 3 shows a cross-sectional view of an embossed print medium thatincludes an image-receiving layer and a leveling composition layer thatwere applied before the print medium was embossed in accordance withexamples of the present disclosure; and

FIG. 4 illustrates a method of preparing an embossed print medium inaccordance with examples of the present technology.

Reference will now be made to several examples that are illustratedherein, and specific language will be used herein to describe the same.It will nevertheless be understood that no limitation of the scope ofthe disclosure is thereby intended.

DETAILED DESCRIPTION

Inkjet printing has permeated many fields where imaging is desirable duein part to its potential to generate high image quality under variousprinting conditions and with various print finishes. For example, someusers of digital printed media desire to print on “embossed” surfaces.Embossing has generally been part of a process by which a texture isintroduced into a surface of a media substrate during manufacturing.Subsequent printing on an embossed surface can provide an aestheticallydesirable end product. However, as the texture depth is increased andthe surface becomes increasingly rough, some print systems, such asinkjet systems, have trouble producing acceptable image quality. Inthese instances, ink can pool in the “valleys” of the textured surface,causing the “peaks” to absorb less ink or to be thinly coated. In otherwords, “ink puddling” can occur in the valleys resulting in non-uniformink coverage and unacceptable image quality.

The present disclosure relates to solving this ink puddling problem,which can improve the printing image quality on surfaces prone to inkpuddling, including embossed surfaces.

Accordingly, the present disclosure is drawn to leveling compositions.In some examples, a leveling composition can include from 80 wt % to 95wt % water, from 0.5 wt % to 15 wt % organic solvent, and from 0.2 wt %to 6 wt % surfactant. Other liquid components can also be present thatform a liquid vehicle. The leveling composition also includes from 1 wt% to 10 wt % cationic ionene polymer having a weight average molecularweight from 100 Mw to 8000 Mw dispersed in the liquid vehicle, and from1 wt % to 10 wt % polymeric binder.

In further detail regarding the leveling composition, the formulationcan be devoid of colorant. In another example, colorant can be present.Still in other examples, optical brighteners, whitening agents, or otheradditives can be present as desired. In another example, the levelingcomposition can include a flame retardant. In another example, the watercan be present at from 85 wt % to 90 wt %, the organic solvent can bepresent at from 1 wt % to 10 wt %, the surfactant can be present at from0.3 wt % to 3 wt %, the cationic ionene polymer can be present at from 2wt % to 8 wt %, and the polymeric binder can be present at from 1 wt %to 8 wt %.

In another example, an embossed print medium can include a mediasubstrate, an image-receiving layer applied to the media substrate at acoating weight of 3 gsm to 50 grams per square meter (gsm), wherein theimage-receiving layer is embossed, and a leveling composition layer isapplied to the image receiving layer at a coating weight of 0.2 gsm to 3gsm. The image-receiving layer can include a pigment filler having anaverage particle size ranging from 0.1 μm to 20 μm and a polymericbinder. The leveling composition layer can include water, an organicsolvent (for example that combines with water to form a liquid vehicle),and a cationic ionene polymer dispersed in the liquid vehicle.

In certain specific examples, the image-receiving layer can be embossedprior to application of the leveling composition, or can be embossedafter application of the levering composition. In either case, theleveling composition can act to prevent puddling that may otherwiseoccur in the valleys of the embossed image. In still further detail, theleveling layer can further include a polymeric binder, a flameretardant, and/or a surfactant. Furthermore, the image-receiving layercan be applied at a coating weight of 5 gsm to 30 gsm and/or theleveling composition layer is applied at a coating weight of 0.5 gsm to2 gsm. In still further detail, the embossed print medium can alsoinclude a base layer applied between the print media and theimage-receiving layer.

In another example, a method of preparing an embossed print medium caninclude applying an image-receiving layer to a media substrate at acoating weight of 3 gsm to 50 gsm, applying a leveling composition layerto the image-receiving layer at a coating weight of 0.2 gsm to 3 gsm,and embossing either the image-receiving layer or the levelingcomposition layer after application. The image-receiving layer caninclude a pigment filler having an average particle size ranging from0.1 μm to 20 μm and a polymeric binder. The leveling composition that isapplied to the image-receiving layer can include a liquid vehicleincluding water and an organic solvent at a ratio of from 1:1 to 98:2,and a cationic ionene polymer dispersed in the liquid vehicle. In oneexample, the image-receiving layer is embossed prior to application ofthe leveling composition layer, and in another example, theimage-receiving layer is embossed after application of the levelingcomposition, i.e. through the leveling composition.

The textured media can be created by embossing and un-embossingtechniques. Such techniques are the processes of creating either raisedor recessed relief images and designs in paper and other materials. Anembossed pattern is raised against the background, while an un-embossedpattern is sunken into the surface of the material. In some examples,the textured media is a media that has been embossed and is capable ofretaining its inherent imaging and performance properties. The texturedmedia can be obtained by embossing a pattern into a media via passingsaid media between rollers with a patterned surface. For purposes of thepresent disclosure, the term “embossed” includes both textured mediathat is either embossed by raising a pattern against a background,un-embossed by sinking a pattern into a background, or a combination ofboth.

A standard embossing machine typically includes two (or more) rollers:an embossing roller and a backing roller. The embossing roller can belaser engraved with a specific pattern that is designed by a graphicdesigner. The backing roller can have a rubber cover or paper/wool typebacking. The print media can pass through the nip between the embossingroller and backing roller. The nip is often pressurized with a hydraulicsystem. After the embossing process, the print media surface will mimicthe design pattern of an embossing roller. The depth of the embossedtexture is dependent on a variety of factors such as paper surfaceproperty, embossing pressure, machine speed, and engraving depth andpattern.

The technique for embossing a texture, pattern, and/or design onto amedia can involve molding the surface of a media by forcing it between apressure nip formed by embossing rollers. The textured printable mediacan also be obtained by using embossing cylinders that may bemechanically or chemically etched with a specific pattern and/or design.The textured media can be created using an embossing roller underpressure. The media is altered during texturing by creating embosseddepths ranging from about 5 μm to about 90 or 150 μm. In certainspecific examples, embossing can produce a peak-valley differentialaverage of about 20 to about 80 μm, about 30 μm to about 70 μm, fromabout 40 μm to about 60 μm. The Parker Print Surface (PPS) roughness canvary from about 0.45 μm to about 127.5 μm at 1600 psi pressure on theembossing roll, for example. As specific examples, the load and depth ofpattern increases the surface roughness. The Confocal microscope Zygosurface roughness can increase from 0.2310 Rq Rz (rmsmic) to 2.0850 RqRz (rmsmic). The static coefficient of friction does not typicallychange but the kinetic coefficient of friction typically slightlydecreases as the surface area is reduced. In some examples, the surfaceroughness of the printable media can be greater than 5 μm per PPSmethod.

With respect to the liquid vehicle that can be used in preparing theleveling composition, notably water and an organic solvent can bepresent, and in some examples, surfactant can also be included. Thewater and organic solvent can be present in the liquid vehicle at aratio of from 1:1 to 98:2, from 2:1 to 95:5, from 3:1 to 90:10, or from4:1 to 50:1.

The organic solvent can be any suitable solvent, and is defined toinclude either a single organic solvent compound or a mixture of organicsolvent compounds. The organic solvent can be in a liquid state at roomtemperature. In one example, the carrier solvent can be a compoundhaving a hydroxyl group, —OH. In one example, the organic solvent can bea water-miscible organic solvent. In one example, the organic solvent(s)can include a short-chain alcohol, short-chain aldehyde, short-chainketone, short-chain ester, short-chain carboxylic acid, or combinationsthereof. “Short-chain,” as used herein, refers to any C1-C6 organiccompound, having a straight or branched chain. In another example, theorganic solvent can be methanol, ethanol, trimethylol propane, propanol,butanol, or combinations thereof. Propanal can include 1-propanol and/or2-propanol (isopropanol). Butanol can include n-butanol, sec-butanol,isobutanol, and/or ten′ butanol. In one example, the organic solvent caninclude acetone, acetonitrile, acetic acid, 1,4-dioxane, pyridine,butanone, methyl acetate, or any other similar solvent. In otherexamples, the organic solvent can be glycerin, glyceryl triacetate,2-ethyl-2-hydroxymethyl-1,3-propanediol, propylene glycol, polyols,diethylene glycol, tetraethylene glycol, polydextrose, 1,5-pentanediol,2-pyrrolidone, N-methylpyrrolidone, ethoxylated glycerol, polyethyleneglycols, or combination thereof. Other example classes of organicsolvents that can be used may include a polyol, a polyol ester, a sugaralcohol, or combinations thereof.

As previously discussed, in one example the organic solvent can be awater-miscible organic solvent. The word “miscible” or “water-miscible”as used herein refers to solvent that can be dissolved in water orotherwise mixed with water at a ratio to form a uniform single-phaseliquid composition. In other words, the components of the liquid vehiclecan be dissolved or mixed without liquid phase separation. However,other components, such as binders and ionene polymers, may be includedin the leveling composition that are not miscible with the liquidvehicle (i.e. these components can be dispersed or suspended in thesingle-phase liquid composition without being dissolved). The uniformsingle-phase liquid composition can have a surface energy greater than85 Dyne/cm, for example.

In one example, the organic solvent is not a water-miscible solvent. Forexample, the organic solvent can form an emulsion or stablemultiple-phase liquid vehicle with water. The multiple-phase liquidvehicle can include emulsifying agents or other stabilizers to maintaina stable multiple-phase liquid vehicle.

In one example, the organic solvent can be present in the levelingcomposition at from 0.5 wt % to 15 wt %. In another example, the organicsolvent can be present in the leveling composition in an amount from 1wt % to 10 wt %. In another example, the organic solvent can be presentin the leveling composition in an amount from 1 wt % to 8 wt %. Inanother example, the organic solvent can be present in the levelingcomposition in an amount from 2 wt % to 5 wt %.

The leveling composition can also include surfactant in some examples.Any suitable surfactant can be used, such as anionic surfactant,cationic surfactant, non-ionic surfactant, or combinations thereof.Several commercially available nonionic surfactants that can be usedinclude ethoxylated alcohols such as those from the Tergitol® series(e.g., Tergitol® 15S30, Tergitol® 15S9), manufactured by Dow Chemical;surfactants from the Surfynol® series (e.g. Surfynol® 440 and Surfynol®465), and Dynol™ series (e.g. Dynol™ 607 and Dynol™ 604) manufactured byAir Products and Chemicals, Inc.; fluorinated surfactants, such as thosefrom the Zonyl® family (e.g., Zonyl® FSO and Zonyl® FSN surfactants),manufactured by E.I. DuPont de Nemours and Company; Alkoxylatedsurfactant such as Tego® Wet 510 manufactured from Evonik; fluorinatedPolyFox® nonionic surfactants (e.g., PF159 nonionic surfactants),manufactured by Omnova; or combinations thereof. Suitable cationicsurfactants that may be used in the leveling composition, for example,include long chain amines and/or their salts, acrylated diamines,polyamines and/or their salts, quaternary ammonium salts,polyoxyethylenated long-chain amines, quaternized polyoxyethylenatedlong-chain amines, and/or combinations thereof.

In one example, the surfactant can be present in the levelingcomposition in an amount from 0.2 wt % to 6 wt %. In another example,the surfactant can be present in the leveling composition in an amountfrom 0.3 wt % to 4 wt %. In another example, the surfactant can bepresent in the leveling composition in an amount from 0.5 wt % to 3 wt%. In another example, the surfactant can be present in the levelingcomposition in an amount from 0.75 wt % to 2 wt %.

In some examples, the levelling composition can include a flameretardant or fire resistant compound. Any suitable flame retardant canbe used. In one example, the flame retardant can be aphosphorus-containing compound. In one example, the flame retardant canbe selected from water-soluble phosphorus-containing compounds. Oneexample of a suitable phosphorus-containing compound is a phosphonateester with a phosphorus-containing closed 4- to 6-membered ringstructure. An example of such a compound is5-ethyl-2-methyl-1,3,2-dioxaphosphorinan-5-yl)methyl dimethylphosphonate P-oxide, having the following structure:

Another example includesbis[(5-ethyl-2-methyl-1,3,2-dioxaphosphorinan-5-yl)methyl] methylphosphonate P,P′-dioxide, having the following structure:

Other phosphonate esters with a phosphorus-containing closed 4- to6-membered ring structure can be selected from some commercial availableproducts, such as FR-102® from Shanghai Xusen Co Ltd, China andAFLAMMIT® from Thor, Germany.

The fire resistant compound can be present, as a percentage of totalsolids, at from 5 wt % to 50 wt %, or from 10 wt % to 40 wt %, thoughthese ranges are only exemplary and are not intended to be limiting. Itis also notable that all of these fire resistant compounds can be usedalone or in combination with one another, or further, in combinationwith phosphor containing esters to provide desired coatingcharacteristics such as viscosity or improved characteristics of thefinished product, including enhanced flame resistance and flexibility.

In one example, the flame retardant or fire resistant compound can bepresent in the total leveling composition in an amount from 0.1 wt % to10 wt %. In another example, the flame retardant can be present in theleveling composition in an amount from 0.2 wt % to 8 wt %. In anotherexample, the flame retardant can be present in the leveling compositionin an amount from 0.3 wt % to 6 wt %. In another example, the flameretardant can be present in the leveling composition in an amount from0.5 wt % to 4 wt %.

Turning now to the ionene polymer, these are polymers having ionicgroups as part of the main chain, meaning that either ionic groups canexist on the backbone unit or ionic groups can exist as an appendinggroup directly attached to an element of the backbone unit, i.e. theionic group is part of the repeat unit of the polymer. The ionenepolymer of the current technology can be either miscible with ordispersible in the liquid vehicle (which includes water, organicsolvent, and in some instances, surfactant or other liquids). In oneexample, the ionene polymer can be dissolved or dispersed in the liquidvehicle after the water and the organic solvent have been mixedtogether. In another example, the ionene polymer can be dissolved ordispersed in either the water or the organic solvent prior to combiningthe water and organic solvent to form the liquid vehicle. In someexamples where the ionene polymer is dispersed in either the water ororganic solvent prior to forming the liquid vehicle, the portion of theliquid vehicle in which the ionene polymer is initially dispersed canalso include surfactant and/or other liquids.

In one example, the ionene polymer can be a cationic charged polymer.For example, the ionene polymer can be a naturally occurring polymersuch as cationic gelatin, cationic dextran, cationic chitosan, cationiccellulose, or cationic cyclodextrin. The ionene polymer can also be asynthetically modified naturally occurring polymer such as a modifiedchitosan, e.g., carboxymethyl chitosan or N, N, N-trimethyl chitosanchloride.

In one example, the ionene polymer is a polymer having ionic groups aspart of the main chain, such as an alkoxylated quaternary polyaminehaving the structure:

where R, R1 and A can be the same group or different groups, such aslinear or branched C2-C12 alkylene, C3-C12 hydroxyalkylene, C4-C12dihydroxyalkylene, or dialkylarylene; X can be any suitable counter ion,such as halogen or other similarly charged anions; and m is a numeralsuitable to provide a polymer having a weight average molecular weightranging from 100 Mw to 8000 Mw. The nitrogens can be quaternized in someexamples.

In another example, the ionene polymer can be a polymer having ionicgroups that append to an element of the backbone unit, such asquaternized poly(4-vinyl pyridine), having the structure:

Again, in this example, the above polymer can repeat to provide apolymer with a weight average molecular weight ranging from 100 Mw to8000 Mw.

In yet another example, the ionene polymer can include polyamines and/ora salts thereof, polyacrylate diamines, quaternary ammonium salts,polyoxyethylenated amines, quaternized polyoxyethylenated amines,polydicyandiamides, polydiallyldimethyl ammonium chloride polymericsalts, or quaternized dimethylaminoethyl(meth)acrylate polymers. Inanother example, the ionene polymer can include polyimines and/or saltsthereof, such as linear polyethyleneimines, branched polyethyleneimines,or quaternized polyethylenimines. In another example, the ionene polymercan include a substitute polyurea such aspoly[bis(2-chloroethyl)ether-alt-1,3 bis[3-(dimethylamino)propyl]urea],or quaternized poly[bis(2 chloroethyl)ether-alt-1,3-bis[3-(dimethylamino)propyl]. In another example, the ionene polymer can bea vinyl polymer and/or a salt thereof, such as quaternized vinylimidazolpolymers, modified cationic vinylalcohol polymers, or alkylguanidinepolymers.

In one example, the cationic ionene polymer can be present in theleveling composition at from 1 wt % to 10 wt %. In another example, thecationic ionene polymer can be present in the leveling composition atfrom 2 wt % to 8 wt %. In another example, the cationic ionene polymercan be present in the leveling composition at from 3 wt % to 7 wt %. Inanother example, the cationic ionene polymer can be present in theleveling composition at from 4 wt % to 6 wt %. Furthermore, in oneexample, the cationic ionene polymer can have a weight average molecularweight of 100 Mw to 8000 Mw.

In some examples, the leveling composition can also contain a polymericbinder to provide good adhesion between the leveling composition layerand image-receiving layer, if desired. The polymeric binder can be anysuitable binder, including non-ionic polymers, cationic chargedpolymers, or any other suitable binder or mixtures thereof. In oneexample, the polymeric binder can include a non-ionic polymer such aspolyvinyl alcohol, vinyl acetate emulsion, or vinylidene chlorideemulsion; or a cationic charged polymer such as cationic starch,polyvinylpyrrolidone, or cationic polyacrylate.

In one example, the polymeric binder can be omitted from the levelingcomposition, but if present, it can be included typically at from 1 wt %to 10 wt % of the dry weight of the total leveling composition weight.In another example, the polymeric binder can be present in the levelingcomposition at from 1 wt % to 8 wt %. In another example, the polymericbinder can be present in the leveling composition at from 2 wt % to 5 wt%. In another example, the polymeric binder can be present in theleveling composition at from 3 wt % to 4 wt %.

In one specific example, the leveling composition can be prepared in ashearing mixer. To illustrate one specific example, a levelingcomposition may include (by weight) 87.5 parts water, 5 parts Floquat®FL 2350 (ionene polymer available from SFN, Inc.), 1 part Zonyl® FSN(fluorosurfactant available from DuPont Co.), 3.5 parts Raycat™ 78(polymeric binder available from Specialty Polymers), 2 parts ofAFLAMMIT® MSG from Thor, Germany, and 3 parts2-ethyl-2-hydroxymethyl-1,3-propanediol (available from Aldrich, Inc.).Concentrations and specific ingredients can be expanded to the rangesand components disclosed herein, for example. The final solids contentafter mixing can be about 11 wt % in this example, but a good range maybe from about 3 wt % to 25 wt % solids content, or from 5 wt % to 15 wt% solids content. The leveling composition layer can be applied to thesubstrate samples at a coat weight of 0.2 gsm to 3 gsm, or from 0.5 gsmto 2 gsm, or from 1 gsm to 3 gsm, for example. A lab coater equippedwith a Mayer rod application station or other applicator can be used tocoat the leveling composition layers, e.g., knife coating device,curtain coating device, etc. Drying can be accomplished in a hot airdrying channel or by application of radiant heat, for example. Theleveling composition can be applied at an overall range of texturedepths at any suitable level. In one example, the levelling compositioncan be applied at a depth of from 5 to 175 microns, 10 to 150 microns,or from 20 to 120 microns. This can be measured with standard surfaceprofilometry equipment, such as contact stylus or non-contact confocalmicroscopy, measuring “Rz.” This parameter, by definition (ASMEY.14.36M/1996), is the average distance between the highest peak and thelowest valley in each sampling.

As previously discussed, the leveling composition can be applied to amedia substrate to prepare an embossed print medium. The media substratecan be prepared from any suitable materials. For example, the supportingmedia substrate can be made of natural fiber and can include naturalcellulose fiber from either a hardwood species alone, or a hardwoodspecies and a softwood species mixed. In one example, a ratio ofhardwood fiber to softwood fiber can be within a range of about 100:0 toabout 50:50. The natural cellulose fibers may be processed into variouspulps including, but not limited to, wood-free pulp, such as bleached orunbleached kraft chemical pulp and bleached or unbleached sulfitechemical pulp; wood-containing pulp, such as one or more of ground woodpulp, thermo-mechanical pulp, and chemo-thermo-mechanical pulp; pulp ofnon-wood natural fiber, such as one or more of bamboo fiber, bagassefiber, recycled fiber, cotton fiber; and a combination of two or morepulps, or a mixture of two or more of pulps. The above fibercompositions of the supporting media substrate may comprise bothsynthetic fibers and natural fibers. An amount of synthetic polymericfiber over the natural fiber may be within a range of about 10 wt % toabout 80 wt % by weight of total fiber. In some examples, the amount ofsynthetic polymeric fiber by weight of total fiber in the mediasubstrate is about 20 wt % to about 70 wt %, or about 30 wt % to about60 wt %. In another example, the support substrate is a polymeric film.

In one specific example, with an understanding that these specificmaterials and weight values are expandable, the media substrate can befabricated using 100 parts of a fiber mixture that includes about 22parts of softwood bleached kraft pulp, 65 parts of hardwood bleachedkraft pulp, and 13 parts recycled fibers. The mixture of pulps andfibers can be machine broken in water. Both softwood and hardwood kraftpulps can be refined separately using a double disc refiner and mixedwith other fibers in the ratio mentioned above. About 20 wt % to about25 wt % fines having an average length of less than 0.1 mm can beincluded in the substrate. A mixture of inorganic particles can be addedinto the fiber furnish to achieve about 13 wt % target ash content. Theinorganic particles can include grounded calcium carbonate powder andTiO2 powder in a weight ratio of 10 parts to 1.5 parts. The substratecan be made using a commercial Fourdrinier® paper machine. After thecomposite web is dried, the web can be brought to a surface size stationwith a rod metering size press machine. A surface size solution can beapplied on the surface of the substrate web and dried.

To these or other media substrates that are capable of receiving andholding an embossed pattern, an image-receiving layer(s) can be appliedfrom an image-receiving layer composition. The function of theimage-receiving layer(s) is to provide an acceptable surface so the inkcan be deposited onto it and generate acceptable print quality. Theimage-receiving layer(s) can facilitate both image quality and imagedurability.

The image-receiving layer can be a single layer or multiple layers withthe same or different coating compositions. The total coat weight of theimage-receiving layer may fall within any suitable range. In oneexample, the dry coating weight can be from about 3 gram per squaremeter (gsm) to about 50 gsm. In another example, the dry coating weightcan range from about 5 gsm to about 30 gsm. In another example, the drycoating weight can range from about 5 gsm to about 20 gsm. In anotherexample, the dry coating weight can range from about 10 gsm to about 20gsm. Application of the coating can be by any method known in the art,including Meyer rod applicator, knife coating applicator, curtaincoating applicator, or the like. Once coated, the image-receivingcomposition dries to form the image-receiving layer. In some examples,the thickness of the image-receiving layer ranges from about 5 microns(μm) to about 40 microns (μm).

In some examples, the image-receiving layer contains pigment filler orfillers. Any suitable pigment filler can be used. The pigment fillerscan be either inorganic and/or organic particulates. The pigment fillerscan be in solid powder form or they can be dispersed in a slurry. Somenon-limiting examples of inorganic pigment fillers include aluminumsilicate, kaolin clay, a calcium carbonate, silica, alumina, boehmite,mica, talc, or combinations or mixtures thereof. The inorganic pigmentfiller can include clay or a clay mixture. The inorganic pigment fillercan include a calcium carbonate or a calcium carbonate mixture. Thecalcium carbonate can be one or more of ground calcium carbonate (GCC),precipitated calcium carbonate (PCC), modified GCC, or modified PCC. Theinorganic pigment fillers can also include a mixture of a calciumcarbonate and clay. In some examples, the inorganic pigment fillers caninclude two different calcium carbonate pigments (e.g., GCC and PCC).

Examples of organic pigment filler include, but are not limited to,particles, either existing in a dispersed slurry or in a solid powder,of polystyrene and its copolymers, polymethacrylates and theircopolymers, polyacrylates and their copolymers, polyolefins and theircopolymers, and combinations thereof. In one example, the pigment fillercan include polyethylene, polypropylene, and combinations thereof.Additionally, the pigment fillers can include silica gel (e.g.,Silojet®703C available from Grace Co.), modified (e.g., surfacemodified, chemically modified, etc.) calcium carbonate (e.g.,Omyajet®B6606, C3301, and 5010, all of which are available from Omya,Inc.), precipitated calcium carbonate (e.g., Jetcoat®30 available fromSpecialty Minerals, Inc.), or combinations thereof. In one example, thepigments can be present at a dry amount ranging from about 50 wt % toabout 95 wt % of the total wt % of the image-receiving layer, or from 65wt % to 85 wt % of the image-receiving layer.

In each of these cases, the pigment filler can have a particle sizeranging from 0.1 μm to 20 μm. In some examples, the pigment filler canhave a particle size ranging from 0.2 μm to 18 μm. In some examples, thepigment filler can have a particle size ranging from 0.5 μm to 15 μm.

In some examples, the image-receiving layer includes a polymeric binder.Any suitable polymeric binder can be used. In one example, the polymericbinder can be an aqueous based polymeric binder. Examples of suitablepolymeric binders include polyvinyl alcohol, styrene-butadiene emulsion,acrylonitrile-butadiene latex, and combinations thereof. Moreover, inaddition to the above binders, other aqueous binders can be addedincluding starch (including oxidized starch, cationized starch,esterified starch, enzymatically denatured starch, and so on), gelatin,casein, soybean protein, cellulose derivatives including carboxy-methylcellulose, hydroxyethyl cellulose and the like; acrylic emulsion, vinylacetate emulsion, vinylidene chloride emulsion, polyester emulsion, andpolyvinylpyrrolidone. Other examples of suitable polymeric bindersinclude aqueous based binders such as polyvinyl alcohol (examples ofwhich include Kuraray Poval®235, Mowiol®40-88, and Mowiol®20-98available from Kuraray America, Inc.), styrene-butadiene emulsions,acrylonitrile-butadiene latex, and combinations thereof. In one example,the amount of the polymeric binder present in the image-receiving layercan be from about 5 to about 40 parts per 100 parts of pigment filler bydry weight. In other examples, the amount of polymeric binder rangesfrom about 7 parts to about 40 parts per 100 parts of the pigment fillerby dry weight, or about 10 parts to about 40 parts per 100 parts of thepigment filler by dry weight, or about 15 parts to about 40 parts per100 parts of the pigment filler by dry weight. In some examples, theamount of polymeric binder in the image receiving layer ranges fromabout 5 parts to about 35 parts per 100 parts of the pigment filler bydry weight, or about 5 parts to about 30 parts per 100 parts of thepigment filler by dry weight, or about 5 parts to about 25 parts per 100parts of the pigment filler by dry weight.

In another example, the image-receiving layer can be a “polymer-rich”composition. A “polymer-rich” composition, as described herein, refersto a composition where the weight percentage of the polymeric fractionin the composition is no less than 20% by weight. In another example,the polymeric fraction of the composition is no less than 40% by weight.A polymer rich composition can provide a printing media with excellentperformance in the areas of ink durability and stain resistance.

Polymer-rich compositions can include a poly-alkene compound, such as apoly-alkene homopolymer, a poly-alkene copolymer, a modifiedpoly-alkene, and combinations thereof. By definition, a “poly-alkene,”as described herein, refers to a polymeric material formed viapolymerization of an alkene monomer, i.e., C_(n)H_(2n) and itsderivatives, where n is within a range of about 7,000 to about 20,000.Some non-limiting examples of poly-alkenes that can be used includepolyethylene homopolymer, polypropylene homopolymer,polytetrafluoroethylene (PTFE), polyamide, amide-modified polyethylene,amide-modified polypropylene, PTFE-modified polyethylene, PTFE-modifiedpolypropylene, maleic anhydride-modified polyethylene, maleicanhydride-modified polypropylene, oxidized polyethylene, oxidizedpolypropylene, chloride polyethylene, chloride polypropylene, andcombinations thereof.

The polymer-rich composition can also include any polymer that shows astrong capability to make a laminating composition on the supportingmedia substrate, or on the surface of the next layer. Some examples ofsuch polymers include, but are not limited to, polyvinyl alcohol,styrene-butadiene emulsion, acrylonitrile-butadiene latex, and anycombinations thereof. In addition to the above binders, other aqueousbinders can be added including: starch (including oxidized starch,cationized starch, esterified starch, enzymatically denatured starch andso on), gelatin, casein, soybean protein, cellulose derivativesincluding carboxy-methyl cellulose, hydroxyethyl cellulose and the like;acrylic emulsion, vinyl acetate emulsion, vinylidene chloride emulsion,polyester emulsion, and polyvinylpyrrolidone. Other examples of suitablepolymeric binders include aqueous based binders such as polyvinylalcohol (examples of which include Kuraray Poval®235, Mowiol®40-88, andMowiol®20-98 available from Kuraray America, Inc.), styrene-butadieneemulsions, acrylonitrile-butadiene latex, and combinations thereof. Inanother example, the polymer-rich composition can include across-linkable polymer such as polyurethane, acrylic-urethane hybridpolymers, and epoxy based polymers.

The image-receiving layer can also include a latex film-forming agent.The latex film-forming agent of the image-receiving layer is provided tofacilitate forming a film of a latex ink (i.e., an image) that may besubsequently deposited on the print medium as an image. The latexfilm-forming agent may be any kind of chemical agent having watercompatibility and temperature volatility that is capable of lowering anelastic modulus of ink latex particulates and of providing temporaryplasticization to promote polymer chain motion to enhance forming alatex ink film from latex ink particulates. Representative examples oflatex film-forming agents include, but are not limited to, citrate orsebacate compounds, ethyoxy alcohols, glycol oligomers and other lowmolecular weight polymers, glycol ether, glycerol acetals, surfactantsthat are either anionic, cationic, or non-ionic and have a backbone ofmore than 12 carbons, cyclic amide-like lactams, e.g., β-lactam,γ-lactam, and δ-lactam, a combination of two or more thereof, or amixture of two or more thereof. In some examples, the latex inkfilm-forming agent is a cyclic amide-like lactam such as β-lactam,γ-lactam, and δ-lactam, or a mixture thereof. In an example, the latexink film-forming agent is a γ-lactam. Representative examples of aγ-lactam include, but are not limited to, N-methyl-2-pyrrolidone,5-methyl-2-pyrrolidone, and 2-pyrrolidone.

A ratio of an amount of the pigment filler to an amount of the filmforming agent may be (by weight) within a range of about 200:1 to about10:1. In some examples, the ratio of the amounts of the pigment fillerto the film forming agent is within the range of about 150:1 to about10:1, or about 100:1 to about 10:1, or about 80:1 to about 10:1, orabout 65:1 to about 10:1, or about 50:1 to about 10:1, or about 35:1 toabout 10:1. In some examples, the ratio of the amounts of the pigmentfiller to the film forming agent is within the range of about 200:1 toabout 15:1, or about 200:1 to about 20:1, or about 200:1 to about 25:1,or about 200:1 to about 30:1, or about 200:1 to about 35:1, or about200:1 to about 40:1. In some examples, the ratio of the amounts of thepigment filler to the film forming agent is within the range of about100:1 to about 11:1, or about 50:1 to about 12:1, or about 35:1 to about13:1, or about 30:1 to about 14:1.

In one specific example, though material choices and ranges outside ofthe amounts given can be expanded as described herein, theimage-receiving composition can be prepared in a high shear mixer. Theimage-receiving composition can include about 80 parts Hydrocarb® 60(available from Omya NA), 20 parts Hydrocarb® 90 (available from OmyaNA), 15 parts Acronal® 866 (available from BASF), 1 part 2-pyrrolidinone(available from Aldrich, Inc.), 0.5 parts Byk-Dynwet® 800 (availablefrom BYK, Inc.), and 0.2 parts BYK® 024 (available from BYK, Inc.). Thefinal solids content after mixing can be from 25 wt % to 75 wt %, e.g.,52 wt %, and the viscosity can be from 120 to 250 centipoise (cps),e.g., 180 cps, as measured by a Brookfield viscometer at 100 rpm. Theimage-receiving layer can be applied to the media substrate samples at acoat weight of 3 gsm to 50 gsm, e.g., 20 gsm with a multi-structuredcoating. A production coater equipped with Mayer rod application stationcan be used to coat the coating layers with a wet-on-dry sequence.Drying can be accomplished in an 8 meter hot air drying channel with atotal coating speed of 30 meters per minute.

As mentioned, the leveling composition is applied to the image-receivinglayer, and in some examples, directly to the image-receiving layer. Inone specific example, the addition of a leveling composition layer to animage-receiving layer at a dry coating weight of from 0.2 gsm to 3 gsmcan improve the print quality (reduce puddling of ink) of an embossedprint medium compared to an embossed print medium with only animage-receiving layer (i.e. without a leveling composition layer). Inone specific example, a leveling composition layer with a dry coatingweight of from 1 gsm to 3 gsm can improve the print quality of anembossed print medium more than an embossed print medium with a levelingcomposition layer at 0.5 gsm dry coating weight.

Turning now to the figures, FIG. 1 shows an example of an embossed printmedium 100. The media substrate 110 has been coated with animage-receiving layer 120. Optionally, a base layer 150 can be includedwith the print medium 120, which is coated over the media substrate. Inaccordance with examples of the present disclosure, the base layer canbe considered to be part of the media substrate in some examples. As canbe seen from FIG. 1, the image-receiving layer has been embossed toprovide the embossed print medium with a textured surface. However, theembossed print medium 100 does not include the leveling compositionlayer. Absence of the leveling composition layer can result in inkpuddling and associated undesirable printing effects.

In contrast, FIG. 2 shows an example of an embossed print medium 200that includes a media substrate 210, an image-receiving layer 220, and aleveling composition layer 230. In one example, a base layer 250 can beincluded with the print medium 220. The leveling composition layer 230can minimize ink puddling and generate a much more aestheticallypleasing print quality. This particular example represents an embodimentwhere the print medium was embossed prior to the application of theleveling composition layer, as can be seen by the leveling compositionnot following the embossing imprint precisely.

FIG. 3 shows another example of an embossed print medium 300. Thisembodiment also includes a media substrate 310, an image-receiving layer320, and a leveling composition layer 330. In one example, a base layer350 can be included with the print medium 320. In contrast to FIG. 2,FIG. 3 represents an embodiment where the print medium was embossedafter the leveling composition layer was applied, as shown by theleveling composition layer embossing more closely following the surfaceof the image-receiving layer. Notably, these FIGS. are schematic innature, so it should not be inferred that embossing would not have animpact on how the layers interface. Rather, what is suggested is thatthe presence of the leveling composition over an image-receiving layerin an embossed format provides superior results with respect to inkpuddling compared to an image-receiving layer without a levelingcomposition overcoat.

FIG. 4 depicts a method 400 of preparing an embossed print medium. Themethod includes various steps, which may or may not follow anyparticular order. Steps can include applying 410 an image-receivinglayer to a media substrate at a coating weight of 3 gsm to 50 gsm,applying 420 a leveling composition layer to the image-receiving layerat a coating weight of 0.2 gsm to 3 gsm, and embossing 430 either theimage-receiving layer or the leveling composition layer afterapplication. The image-receiving layer can include a pigment fillerhaving an average particle size ranging from 0.1 μm to 20 μm and apolymeric binder. The leveling composition that is applied to theimage-receiving layer can include a liquid vehicle including water andan organic solvent, and a cationic ionene polymer dispersed in theliquid vehicle. In one example, the image-receiving layer is embossedprior to application of the leveling composition layer, and in anotherexample, the image-receiving layer is embossed after application of theleveling composition, i.e. through the leveling composition.

It is noted that, as used in this specification and the appended claims,the singular forms “a,” “an,” and “the” include plural referents unlessthe content clearly dictates otherwise.

“Substrate” or “media substrate” includes any base material that can becoated in accordance with examples of the present disclosure, such asfilm base substrates, polymer substrates, conventional paper substrates,photobase substrates, offset media substrates, and the like. Further,pre-coated and film coated substrates can be considered a “substrate”that can be likewise be coated in accordance with examples of thepresent disclosure.

As used herein, the term “about” is used to provide flexibility to anumerical range endpoint by providing that a given value may be “alittle above” or “a little below” the endpoint. The degree offlexibility of this term can be dictated by the particular variable andcan be determined based on experience and the associated descriptionherein.

As used herein, a plurality of items, structural elements, compositionalelements, and/or materials may be presented in a common list forconvenience. However, these lists should be construed as though eachmember of the list is individually identified as a separate and uniquemember. Thus, no individual member of such list should be construed as ade facto equivalent of any other member of the same list solely based ontheir presentation in a common group without indications to thecontrary.

Concentrations, dimensions, amounts, and other numerical data may bepresented herein in a range format. It is to be understood that suchrange format is used merely for convenience and brevity and should beinterpreted flexibly to include not only the numerical values explicitlyrecited as the limits of the range, but also to include all theindividual numerical values or sub-ranges encompassed within that rangeas if each numerical value and sub-range is explicitly recited. Forexample, a weight ratio range of about 1 wt % to about 20 wt % should beinterpreted to include not only the explicitly recited limits of 1 wt %and about 20 wt %, but also to include individual weights such as 2 wt%, 11 wt %, 14 wt %, and sub-ranges such as 10 wt % to 20 wt %, 5 wt %to 15 wt %, etc.

As a further note, in the present disclosure, it is noted that whendiscussing the levering compositions, the embossed print medium, and themethod of preparing the embossed print medium, each of these discussionscan be considered applicable to each of these examples, whether or notthey are explicitly discussed in the context of that example. Thus, forexample, in discussing details about the levering compositions per se,such discussion also refers to the embossed print medium and method ofpreparing an embossed print medium described herein, and vice versa.

The following illustrate examples of the disclosure. However, it is tobe understood that these examples are merely exemplary or illustrativeof the application of the principles of the present disclosure. Numerousmodifications and alternative compositions, methods, and systems may bedevised by those skilled in the art without departing from the spiritand scope of the present disclosure. The appended claims are intended tocover such modifications and arrangements.

EXAMPLES Example 1—Media Substrate

A media substrate was prepared using 100 parts of a fiber mixture thatincludes about 22 parts of softwood bleached kraft pulp, 65 parts ofhardwood bleached kraft pulp, and 13 parts recycled fibers. The mixtureof pulps and fibers were machine broken in water. Both softwood andhardwood kraft pulps were refined separately using a double disc refinerand mixed with other fibers. About 20 wt % to about 25 wt % fines havingan average length of less than 0.1 mm were included in the substrate. Amixture of inorganic particles were added into the fiber furnish toachieve about 13 wt % target ash content. The inorganic particlesincluded grounded calcium carbonate powder and TiO₂ powder at a weightratio of 10 parts to 1.5 parts. The substrate was made using acommercial Fourdrinier paper machine. After the composite web was dried,the web was brought to a surface size station with a rod metering sizepress machine. A surface size solution was applied on the surface of thesubstrate web and dried.

Example 2—Image-Receiving Layer

An image receiving layer was prepared to coat on the media substratedescribed in Example 1 according to the following table:

TABLE 1 Image-Receiving Composition Amount Ingredient Suppliers (Partsby Weight) Hydrocarb ® 60 Calcium carbonate pigment 80 fillers from OmyaNA Hydrocarb ® 90 Calcium carbonate pigment 20 fillers from Omya NAAcronal ® 866 Styrene-acrylic substance 15 from BASF Corporation2-pyrrolidinone Aldrich Inc. 1 Byk-Dynwet ® 800 Silicone-free wettingagent 0.5 from BYK Inc. BYK ®-024 VOC-free silicone defoamer 0.2 fromBYK Inc.

The image-receiving composition was prepared in a high shear mixer. Thefinal solids content after mixing was 52 wt % and the viscosity was 180centipoise (cps), as measured by a Brookfield viscometer at 100 rpm. Theimage-receiving layer was applied to the media substrate samples at acoat weight of 20 gsm with a multi-structured coating. A productioncoater equipped with Mayer rod application station was used to coat thecoating layers with a wet-on-dry sequence. Drying was accomplished in an8 meter hot air drying channel with a total coating speed of 30 metersper minute.

Example 3—Leveling Composition

The leveling composition layer was prepared and applied from a levelingcomposition according to Table 2, as follows:

TABLE 2 Leveling Composition Ingredient Suppliers Amount (Parts) H₂O LabDe-ionic water 87.5 Floquat ® FL 2350 SFN Inc 5 (cationic ionenepolymer) Zonyl ® FSN DuPont Co 1 (fluorosurfactant) Raycat ™ 78Specialty Polymers 3.5 (polymer binder) 2-ethyl-2-hydroxymethyl- AldrichInc 3 1,3-propanediol (organic solvent) Note - In one example, theleveling composition of Table 2 can be modified with the addition of aphosphorus-containing flame retardant, e.g., about 2 wt % Aflammit ® MSGfrom Thor Ltd, Germany.

The leveling composition was prepared in a shearing mixer. The finalsolids content after mixing was about 11 wt %. The leveling compositionlayer was applied to the substrate samples at a coat weight of 1 gsm to3 gsm. A lab coater equipped with a Mayer rod application station wasused to coat the leveling composition layers. Drying was carried outusing a hot air drying channel.

The leveling coating can be applied either before or after embossing.However, in the current examples, the substrate was embossed with anembossing machine after coating the image-receiving layer (but beforethe leveling composition was applied), as shown in FIG. 2. The embossingleft a peak-valley differential average of about 50 microns. The overallrange of texture depths at which the levelling composition was appliedwas from 10 to 150 microns. This can be measured with standard surfaceprofilometry equipment, such as contact stylus or non-contact confocalmicroscopy, measuring “Rz.” This parameter, by definition (ASMEY.14.36M/1996), is the average distance between the highest peak and thelowest valley in each sampling.

Example 4—Print Quality and Puddling Evaluation

The embossed print media prepared in accordance with Example 3 (SampleA) was evaluated against other print media that did not include theleveling composition (Sample B), was not embossed (Sample C), or was notembossed and the leveling composition not applied (Sample D). Eachsample was printed on using a 60-inch wide, large format, thermal inkjetprinter with a 6-ink color system: cyan, magenta, yellow, black, lightcyan, and light magenta. Each of the inks was a pigmented aqueous inkwith added latex for durability. The print mode was a 16-pass,bidirectional, in native color mode (no color rendering), and the heaterwas at setpoints of 50° C. and 110° C.

Each sample was examined visually by multiple inspectors under acontrolled light box with D65 fluorescent lighting following anestablished procedure, i.e. ISO 10526:1999/CIE 5005/E-1998. Apart fromgenerating numeric data, like optical density and gamut, the inspectorslooked specifically for overall image quality and gave each of thesamples a simple rating from 1 (poor image quality) to 5 (good imagequality). For this test specifically, 1 was attributed to ink puddling,which is where the ink density appears higher in the troughs or valleysof the texture and less on the peaks of the texture. Scores 2, 3, and 4differentiate puddling levels in decreasing order, and a score of 5 wasattributed with uniform coverage of the ink in both the valleys and thepeaks of the embossed texture.

Sample A was prepared as described in Example 3. The media substrate wascoated with an image-receiving layer, and the print medium wassubsequently embossed. A leveling composition layer was then applied tothe print medium. Finally, the print medium was printed and evaluated.Sample A received a print rating of 5.

Sample B was prepared in the same way as Sample A, except the levelingcomposition layer was not applied to the print medium. Sample B receiveda print rating of only 1.

Sample C was prepared in the same way as Sample A, except the printmedium was not embossed. Sample C received a print rating of 5.

Sample D was prepared in the same way as Sample A, except that printmedium was not embossed and the leveling composition layer was notapplied. Sample D received a print rating of 5.

These examples illustrate that applying the leveling composition layerstill provides good image quality when there is no embossing present(Sample C). Further, the image quality remains high without the levelingcomposition when the print medium is not embossed (Sample D), indicatingthat the embossing introduces the problems of puddling associated withpoor image quality. In other words, without embossing, there is no needfor the leveling composition. However, when the media is embossed, theleveling composition has the impact of making acceptable an otherwisepoor surface for achieving high print quality.

Example 5

Various coating weights of a leveling composition layer were applied toan embossed print medium to determine what levels would be effective atovercoming ink puddling. Four leveling composition layer coating weightswere applied and visually assessed with the print rating scale describedabove in Example 4. Specifically, coating weights of 0.5 gsm, 1 gsm, 1.5gsm, and 2 gsm were tested.

The coating weight of 0.5 gsm received a print rating of 4, which isvery good. However, coating weights of 1 gsm, 1.5 gsm, and 2 gsm allreceived print ratings of 5. This example illustrates that even verysmall coating weights of the leveling composition can significantlyimprove the overall print quality on an embossed print medium. Eventhough a coating weight of 0.5 gsm received a print rating of 4, theprint quality was still improved over Sample B in Example 4 (from 1 to4) where the print medium was embossed, but no leveling compositionlayer was applied.

This technology has been described with reference to certain examples,and those skilled in the art will appreciate that various modifications,changes, omissions, and substitutions can be made without departing fromthe spirit of the disclosure. It is intended, therefore, that thepresent disclosure be limited only by the scope of the following claims.

What is claimed is:
 1. An embossed print medium, comprising: a mediasubstrate; an image-receiving layer applied to the media substrate at acoating weight of 3 gsm to 50 gsm, wherein the image receiving layercomprises a pigment filler having an average particle size ranging from0.1 μm to 20 μm and a polymeric binder, wherein the image-receivinglayer is embossed; and a leveling composition layer applied at a coatingweight of 0.2 gsm to 3 gsm to the image-receiving layer, wherein theleveling composition layer comprises a cationic ionene polymer.
 2. Theembossed print medium of claim 1, wherein the image-receiving layer isembossed after the leveling composition layer is applied to the mediasubstrate.
 3. The embossed print medium of claim 1, wherein theimage-receiving layer is embossed prior to application of the levelingcomposition layer.
 4. The embossed print medium of claim 1, wherein theleveling composition layer further comprises a polymeric binder.
 5. Theembossed print medium of claim 1, wherein the leveling composition layerfurther comprises a phosphorous-containing flame retardant.
 6. Theembossed print medium of claim 1, wherein the image-receiving layer isapplied at a coating weight of 5 gsm to 30 gsm.
 7. The embossed printmedium of claim 1, wherein the leveling composition layer is applied ata coating weight of 0.5 gsm to 2 gsm.
 8. The embossed print medium ofclaim 1, further comprising a base layer applied between the mediasubstrate and the image-receiving layer.
 9. The embossed print medium ofclaim 1, wherein the leveling composition layer is applied using aleveling composition including the cationic ionene polymer and a liquidvehicle including water and an organic solvent.
 10. A method ofpreparing the embossed print medium of claim 1, comprising: applying theimage-receiving layer to the media substrate; applying the levelingcomposition layer to the image-receiving layer; and embossing theimage-receiving layer.
 11. The method of claim 10, wherein theimage-receiving layer is embossed prior to application of the levelingcomposition layer.
 12. The method of claim 10, wherein theimage-receiving layer is embossed after application of the levelingcomposition layer.
 13. The method of claim 10, wherein the levelingcomposition layer is applied using a leveling composition including thecationic ionene polymer and a liquid vehicle including water and anorganic solvent.
 14. The method of claim 13, wherein the water and theorganic solvent are present in the leveling composition at a weightratio of from 1:1 to 98:2.
 15. The method of claim 10, wherein theleveling composition layer further comprises a polymeric binder.
 16. Themethod of claim 10, wherein the leveling composition layer furthercomprises a phosphorous-containing flame retardant.
 17. The method ofclaim 10, wherein the image-receiving layer is applied at a coatingweight of 5 gsm to 30 gsm, and the leveling composition layer is appliedat a coating weight of 0.5 gsm to 2 gsm.
 18. The method of claim 10,further comprising applying a base layer between the media substrate andthe image-receiving layer.